Question

calculate the no. of moles
(i)84 grams of nitrogen
(ii)8.066×10²³ no. of nitrogen atoms

Answer 1

I)Given mass of N atom = 84 g
Molar mass of N atom = 14 g
Therefore number of moles in 84 g of N atoms,
n = m/M
n = 84/14
n = 6  
Therefore 6 moles of N atoms contain 84 grams …
II)Given particles = 8.066 * 10²³
Number of particles in N atoms = 6.022 * 10²³ 
Therefore number of moles in 8.066 * 10²³,
n = 8.066 * 10²³/6.022 * 10²³ 
n = 8.066/6.022
n = 1.33
therefore number of moles in 8.066 * 10²³ particles = 1.3 
 i hope it helps....